Tube and method of manufacturing the same



May l9, l fi. 5 LAURENT 2,041,2"YU TUBE AND METHOD OF MANUFACTURING THE SAME Filed Oct. 25, 1955 2 Sheets-Sheet 1 INVENTOR HERBERT ST. LAURENT W, H. sT. LAURENT fl v TUBE AND METHOD OF MANUFACTURING THE SAME Filed Oct. 25, 1955 2 Sh e'ets-Sheet 2 INVENTOR HERBERT ST. LAURENT M TORNEYS 1 Patented May 19, 1936' PATENT oFFicE EriiBi: METHOD OF MANUFACTURING I THE SAME Herbert St. Laurent, Hastings "upo'i'i Hudson,

N. Y., assignor to Radio Inc., New York, N. ware Research Laboratories,

Y., a corporation of Dela- Application October 23, 1933, Serial No. 694,738

2 Claims.

This invention relates to electric discharge tubes and methods of manufacturing the same, and particularly to tubes having an appreciable gas content adaptable for use as amplifiers, repeaters, detectors, etc. of electrical impulses.

In my copending application Serial No. 605,189, filed April 14, 1932, I have disclosed tubes of this kind. In that application it is disclosed that it is of vital importance that there be no leakage paths or so-called alternative or short-path effects between adjacent electrodes. That application also discloses particular types of mounting elements and electrodes for preventing such leakage paths.

I have now developed a new method of making tubes of the kind disclosed in the aforementioned application, which has proved very satisfactory in the elimination of such leakage paths. My new invention consists in molding the electrode supporting element, and leads to the electrodes projecting therethrough to the stem of a tube while such stem is in a viscous state so that all irregularities which may exist between a stem and an insulator are completely eliminated.

In the drawings- Figure 1 is an elevation of the stem, insulator and electrode connections for a tube of one form of my invention;

Fig. 2 is a plan view of a die block used in my new method;

Fig. 3 is a cross-section along line 3--3 of Fig. 2:

Fig. its a side View at right angles to Fig. 1 of the apparatus shown in Fig. 1 with the die block in position;

Fig. 5 is a side view of the assembly of another form of tube;

Fig. 6 is a view of the die block for use in assembling the tube of Fig. 5;

Fig. 7 is a View corresponding to Fig. 4 for the tube of Fig. 5;

Fig. 8 is a view of an end insulator or cap for the electrodes of the type shown in Fig. 5;

Fig. 9 is a side elevation of one of the electrodes for the tube of Fig. 5 with a lead attached thereto; and

Fig. 10 is a View of an intermediate insulator and electrode support for the tube of Fig. 5.

In my copending application heretofore referred to I disclose a tube in which the electrodes are concentrically mounted on an insulator having annular sections of consecutively larger diameter on which the electrodes are mounted.

In assembling such a tube in accordance with the present invention I employ a die block I, having a form adapted to accommodate an insulator 2 and provided with longitudinal slots (Fig. 3) into which the electrode supporting members 4 may be inserted. These electrode supporting members project through the insulator 2 and are connected to leads for the various electrodes, as shown in Fig. 1. I then place a piece of glass tubing, which is to be molded to form the stem of my tube, in position over the die block and turn the die block and tubing in a flame in the usual manner, in order to soften the tubing. When the tubing has become sufficiently soft for pinching I pinch it in the usual manner. Inasmuch as the insulator 2 is in position in the die block at the time of this pinch, andthe glass tubing 15 is in viscous condition, the glass molds itself to the insulator 2 and provides an electron-proof sealed connection between the stem and the insulator. The tube may then be completed by adding the electrodes, sealing an envelope over the electrodes,

0 adding a base, evacuating the envelope, and filling it with whatever type of gas it is desired to use.

In Figs. 5 to 10 I have shown the assembly of a tube with a different type of electrodes. this case the electrodes 5 (Figs. 7 and 9), which may be made of interwoven wire mesh, are arranged parallel to one another and seated in caps 6 and intermediate insulators I. The caps 6 are of insulating materal and closed at one side, 30

and are provided with collars 8 in which the electrodes 5 seat, and grooves 9 through which leads for the electrodes project. Similarly, the intermediate insulators 1 are provided with collars ID to seat the electrodes and which the electrode leads project. In connection with tubes of this kind I employ a die block of the kind shown in Fig. 6. The electrode assembly consisting of two caps and a sufficient number of intermediate insulators to accommodate the 40 number of electrodes to be used, are assembled in this die block and held in assembled position by tightening a screw l2. The glass tubing which is to form the stem is then placed in position over the leads l3 from the electrodes, and the 45 tubing and die block are turned in the usual manner so that a flame plays on the end of the tubing. When the tubing becomes sufficiently viscous it is pinched into position in the usual manner,

and this forms a perfect seal between the stem so formed and the insulators enclosing the electrodes. A metallic band of suitable material, such as nickel, may then be fastened around the electrode assembly to hold the end caps in position. This band is also useful in evacuating grooves ll through 35 the tube as it may be heated by high frequency induction to expel occluded gases. The tube may then be completed by adding the other necessary apparatus to form a completed assembly, as shown in Fig. 5.

The die blocks may of course have hollow cylindrical bodies and be provided with an adjustable drilled member to accommodate the lead wires.

What is claimed is:

1. A tube comprising an insulator, a plurality of closed concentric electrodes mounted on said insulator and forming an electron seal with said electrodes projecting insulator, a plurality of leads connected to said electrodes and projecting through said insulator, a stem, and an electron-proof seal between said stem and said insulator formed by molding said stem to said insulator.

2. A tube comprising a plurality of cylindrical insulators, a plurality of disc-shaped electrodes mounted within said insulators, leads for said through said insulators, a stem, and an electron-proof seal between said stem and said insulators formed by molding said stem to said insulators.

HERBERT ST. LAURENT. 

